Receive the latest breaking updates in your inbox

Authorities are searching another location in suburban Colorado hours after they entered the home of a Denver man, who sparked a series of anti-terror raids in Queens, looking for evidence to see if he has any ties to terror.

Investigators with search warrants entered a home belonging to the relatives of Najibullah Zazi, an Afghan immigrant who has not been charged or arrested and proclaimed his innocence through a lawyer on Tuesday. Television station KUSA reports a tarp is set up outside, suggesting examination of evidence may be being prepared.

Hours ago, FBI agents entered the Denver home of Zazi to conduct a search. It wasn't immediately known if Zazi was at his home in Aurora at the time of the raid. His attorney, Arthur Folsom, was not at his Denver office and couldn't immediately be reached for comment.

One agent wearing protective clothing escorted a dog belonging to the Bureau of Alcohol, Tobacco, Firearms and Explosives into Zazi's apartment. Another wore a shirt with the words "FBI Evidence Response Team'' on it. Other agents wearing FBI jackets stood outside the building along with Arapahoe County sheriff's deputies.

The raid came a day after two law enforcement officials told The Associated Press that a joint FBI-New York Police Department task force had put Zazi under surveillance because of suspected links to al-Qaida.

Zazi spoke out on Tuesday, denying any connection with terrorist organizations and saying, through his lawyer, "I love America."

His attorney said the FBI is focusing on the wrong man, and told KUSA television station in Denver that his client has agreed to be questioned by the FBI.

Zani's car and computer were seized while he was attempting to cross the George Washington Bridge earlier this week and his visit to New York prompted a series or FBI-NYPD raids around Queens.

Officials said they are still trying to learn more about Zazi and his associates in both Queens and Colorado, while evidence recovered in the Queens raid has been sent to the FBI lab at Quantico, Va., for additional analysis. Agents are also scouring Home Depot and other stores in the Denver area to whether people on watch lists made any unusual purchases such as muriatic acid, which can be used to make bombs more deadly, sources said.

As NBC New York first reported, officials said they recovered a document on how to build a bomb during the searches.

Investigators also said they seized nine backpacks in the Queens raids but no evidence of explosives were found. Officials said they were looking to see if the backpacks were all bought recently and at the same time.

Several law enforcement officials have pointed out backpacks have been used to conceal bombs in attacks on trains in Madrid and London – but a senior official briefed on the case said there is no evidence of any plot to target New York area trains at this time.

Officials said no warning has been issued in this case because there is no evidence at this time suggesting any of the men discussed possible targets.

News of today's raids in Denver comes on the heels of one official stressing there is no need for any public threat warning at this time.

That official pointed out how months ago, Homeland Security officials put out an unrelated warning about a possible threat to the Long Island Rail Road. A Long Island man admitted speaking with Al Qaeda operatives overseas about the transit system, prompting the alert.

On Capitol Hill today, FBI director William Mueller added, "I don't believe there's an imminent danger from what I know of that particular investigation."

Sen. Charles Schumer had asked the FBI chief to reassure New Yorkers and Americans that the case did not pose a ready danger and that any plot was not in an executable stage.

“This recent report put New Yorkers on edge. It came at a time right after 9/11. There are all sorts of rumors going around. I know that this is an ongoing investigation and not much can be said, nor should it, so the investigation is not compromised,” Schumer said at the hearing.

Police Commissioner Ray Kelly said he won't comment on the investigation generally, or the backpacks in particular, saying only the investigation continues. Kelly denied reports suggesting a riff between the FBI and NYPD in the case over whether the NYPD pushed to have the raids happen sooner rather than to conduct surveillance on the men for a while longer.

Yesterday, the New York Post reported that the FBI is miffed with the NYPD for allegedly flubbing the intelligence gathering effort in Queens -- and tipping off the suspect.

Colorado elected officials who said they've been briefed on the investigation have said there is no imminent threat.

Zazi, 24, had holed up in his Denver-area apartment earlier Wednesday, not wanting the media storm surrounding his case to cause trouble for his company, his boss said.

The building is very close to a toll road that runs to Denver International Airport, where Zazi picks up and drops off passengers as a driver for ABC Airport Shuttle. Zazi's airport shuttle van was parked outside the building.

ABC Airport Shuttle dispatcher Tony Gonzales said he spoke to Zazi after the media storm erupted and Zazi said he was staying home to avoid giving his company any trouble.

"We don't have any problem, he can always come back and work here,'' said Gonzales, 48.

"He's a hardworking guy. No trouble, no problem whatsoever. Very quiet guy,'' Gonzales said. "He's always on time. When we give him a pickup, he always does it.''

On Tuesday, Folsom said Zazi contacted him immediately after hearing that friends' homes in New York had been raided.

The lawyer said Zazi drove to New York in a rented car to take care of a problem with the location of a coffee cart that he co-owns with a friend, and to visit friends.

Zazi said he was stopped by police on Sept. 10 on the George Washington Bridge, which connects New Jersey to Manhattan, and that he consented to a random search of his vehicle for drugs. He was allowed to leave.

In New York, Folsom said, Zazi's car was towed because of a parking violation. Police searched both the car and a laptop inside, Folsom said.

"They found nothing, didn't ask him any more questions and sent him on his way,'' Folsom said. "If they had had found anything, he would be in the company of the federal officials in New York.''

Zazi returned the car to an airport and flew home to Denver.

Zazi's aunt, Rabia Zazi, said that her nephew recently visited the Peshawar region of Pakistan _ where she said his wife lives. Najibullah Zazi hopes to bring his wife to the United States, his aunt said.

She said Zazi was born in Pakistan but moved to the United States at an early age and grew up in Queens. He moved to Colorado several months ago to help his father with his shuttle business, she said.

Gonzales said Zazi had left another shuttle company for ABC, where drivers are more independent and can set their own hours. He said he was surprised to hear news reports about Zazi.

"When I called, he said, 'I'm home.' I said, 'What the hell are these people talking about."